[Note: The QT interval involves the heart’s electrical system and the activity of the ion channels that transport positively charged potassium atoms (ions) across the membrane of cardiac muscle cells, into and out of the cells, to maintain the heart’s normal rhythm. The QT interval is the time between the start of the Q wave and end of the T wave in the heart’s electrical cycle. The faster the heart rate, the shorter the QT interval.]

One previous study of a selected population using a manual measurement technique suggested CFS is associated with a shortened QTc interval. [QTc stands for ‘corrected QT’ - a way of estimating what QT interval would be at a heart rate of 60 bpm, as a way of comparing QT over time.]

Here we assessed QTc in a large UK population of CFS patients using automated, clinically applicable, measurement techniques, and confirmed that QTc is significantly shortened in CFS patients compared to non-CFS fatigued and control populations.

Automated measurement of QTc in clinical practice has potential utility as a diagnostic biomarker in CFS.